Cannula



Jan. 1, 1946. D s 2,392,045

CANNULA Filed Dec. 27, 1 944 Patented Jan. 1, 1946 UNITED STATES PATENT OFFICE I CANNULA Archibald P. Hudgins, Charleston, W. Va.

Application December 27, 1944, Serial No. 570,016

4 Claims.

This invention relates to a surgical cannula for the diagnosis and treatment of occlusion of the Fallopian tubes.

The general object of the invention is to provide a valved cannula, self-retained in the cervix of the uterus, through which air or liquid may be introduced under pressure' to distend the uterus, and retained for long periods of time, if desirable.

One of the specific objects of the invention is to provide a tapered cannula, externally threaded, so as to be retained in place solely'by its direct threaded engagement with the wall, of the cervix, the undulatin interface between the surface of the threads and the contacting membrane of the cervix affording an extended pneumatic seal of great efficiency in holding air or liquid under pressure within the uterus.

Referring particularly to Figure 2, beginning at a diametrical plane ab, which may be approximately 0.7 centimeter from the outer end,

Another object of the invention is to provide I a cannula of the type described, having a threaded insertable portion of gradual taper, and an unthreaded portion at'its outer end, of wider taper, presenting a smooth surface to the surrounding vaginal tissue, and having a widened bore forming a seat for the nozzle of an air pump or syringe.

A further object of the invention is the provision of a readily removable check valve in the bore of the cannula, to facilitate cleansing and sterilization of the instrument.

Another object of the invention is to provide in combination, the cannula and a handle for inserting or removing the same, with detachable interengaging means whereby the handle is gradually disassociated from the cannula/While the latter is being carried by the patient.

Other objects of the invention will appear as the following description of a preferred and practical embodiment thereof proceeds.

In the drawing which accompanies and forms a part of the following specification:

Figure 1 is a perspective view of the cannula with the handle attached;

Figure 2 is a longitudinal axial sectional view;

Figure 3 is an end elevation of the larger end;

Figure 4 is a fragmentary view of the cannula engaging end of the handle.

Referring now in detail to the several figures, the numeral 1 represents the body of the cannula which is preferably made from a noncorrosive metal such as stainless steel. In actual size, it may be 5 centimeters in length, 2 centimeters in diameter at its larger end, and 0.7 centimeter in diameter at its smaller end, although the dimensions are not critical to the invention.

the outer contour of the cannula follows a gradual uniform taper to its inner end. This portion of the cannula which is designated as 2, is designed to be inserted in the cervix, and is formed with a thread 3; preferably in clockwise direction. The thread is preferably rounded to avoid abrasion or chafing.

That portion 4 of the cannula extending from the plane 11-12 to the outer end, is designed to remain outside of the cervix. It is unthreaded, presenting a smooth comfortable surface to the surrounding vaginal tissue. It is tapered more widely than the threaded portion 2, principally to accommodate the conical depression 5, which opens in the outer end of the cannula and forms a seat for the nozzle of an air pump or a syringe.

. The inner portion 2-has an axial bore 6 communicating with the conical depression 5, and with an enlarged counterbore l, forming a chamber for the ball check valve 8, which seats against the shoulder formed at the juncture of the bore and counterbore. A spring 9 biases the valve 8 toward its seat. A plug l0, having an axial bore ll, screws into the counterbore 1, against the spring 9. The end of the plug preferably terminates flush-with the inner end of the cannula and has a kerf l2 engageable by a suitable blade by means of which the plug may be readily removed. Thus, the plug, spring and ball valve may be separated from the body of the cannula to facilitate cleansing and sterilizing.

A handle I3 is provided for inserting and withdrawing the cannula. The outer portion 14 of the handle is preferably formed with a roughened gripping surface, while the inner end l5 has the laterally extending pins I6, which snugly fit in corresponding recesses I! in the outer end of the cannula.

To insert the instrument, the handle is turned in a clockwise direction until the cannula has been screwed in to the proper distance. The handle is then removed. To withdraw the cannula th handle is reengaged with it and turned in a counterclockwise direction.

The advantages of this instrument are many. It facilitates the procedure of X-raying the Fallopian tubes by minimizing the p instrumentation necessary. The cannula is self-retained. It can be inserted in the ofiice of the physician. Bulky retaining tennacula and forceps are not required. Th instrument being small and self-retained, it permits the patient to be ambulatory so that tic purposes, to be retained for a, period of;

twenty-four hours or longer. This allows the gradual muscular contractions of the uterus to,

exert gentle, sustained, prolonged pressure on,

the tubes. This type of pressure is more effective in overcoming obstruction of the tubes than the sudden, quick, painful injection which is the only method available in the use- (Sf previous instru ments. The spasm of th tubes, so frequently found during other methods of examination, by previously available instruments, is. overcome when thiscannulaandmethodwe used; This is due to the-prolonged, gradual,- rhythmic contractions of theuterus which allows relaxationof the muscular bands around the Fallopian tubes.

While I have in the above disclosure described what I believe tobe-a preferred and practical embodiment of the invention, it will be understood to those skilledin the art that-thespecific detailsof construction and arrangement of parts-areby wayof example and not to be construed as limitmg the scopeof the invention.

What! claim as myinvention is:

1. Cannula-comprising-a frusto-conical body-- having a; portion with gradual uniform taper beg-inning -at a diametrical plane nearits larger end and extending =to its smaller-end, said portion-beingexternally threaded, saidbody having a lportionof wider taper beginning at its outer end and extending to said d-iametrical plane; the latter portion being externally unthreaded, said body having a longitudinal bore therethrough with a flaring mouth opening in th larger end of said body forming a seat for the nozzle of an air pump or syringe, and a check valve in said bore opening toward the smaller end of said body.

2. Cannula as claimed in claim 1, the external thread being rounded.

3. Cannula comprising a frusto-conical body having a portion with gradual uniform taper beginning at a diametrical plane near its larger endand extending to its smallervend, said body being-externally threaded; said body having a portion of wide taper beginning at its outer end and extending to said diametrical plane, the latterportion being externally unthreaded, said body having a longitudinal bore therethrough with a flarin mollthrahone end opening in the larger end of said bore forming a seat for the nozzle of an air pump or syringe, a check valve seated in said bore opening toward the smaller end of said body, a spring in said bore biasing said valve toward closed position and ana-nnular plug screwed in the inner endof said =bore against said spring, said valve, spring and plug beingreadily removable.

4. Externally threadedcannula adapted to be rotated forinsertiomor-removal by atool having a tapered end with diametrical projections on opposite sides at the base of 'the'tapered end; said cannula comprising an externally threaded'tapered body having a -bore-therethrough with flaring mouth opening inthe larger endofthe body adapted to receive and center the tapered endof the tool, said body being formedqwith diametrically opposites'lotsopening in the ,face of the,

larger end andinto said flaringmouth, adapted to receive the projections onthe toolto couple said tool and cannula, the latter. having a check valve in said bore opening toward the smaller end of ,said cannula.

ABCHIBALD P; HUDGINS. 

